>> the actions of north korea are a threat to regional peace and security, international peace and security, and they are not acceptable. they will not be tolerated. and they will be met with north korea's increasing isolation and pressure under united nations sanctions. >> reporter: the security council was quick to condemn the test. it also responded quickly in december when north korea successfully launched a long-range missile. the test could bring north korea closer to developing a nuclear warhead that is small enough to be mounted on a missile. critics point out that the security council members feel that the threat of north korea's program is becoming more real than ever before. >> so miki, what's next? will the security council adopt tougher sanctions against north korea? >> reporter: well, the u.s., along with south korea, australia, and european members are all for tougher sanctions.